Presulfiding OCR catalyst replacement batches

ABSTRACT

Catalyst particles are presulfided in a treatment zone separate from a hydroconversion reaction zone. The presulfided catalyst is then added to a substantially packed bed of catalyst in the hydroconversion reaction zone at reaction pressure, so that the reactor is not shut down to replace catalyst. The presulfiding process is particularly beneficial for use in moving bed reactors for heavy oil conversion.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is a Continuation-in-Part of copendingapplication U.S. Ser. No. 09/465,122, filed on Dec. 16, 1999 and claimspriority therefrom.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to a method for extending thecatalytic life of catalyst used in hydroprocessing of a hydrocarbon feedstream. More particularly, the present invention provides for a methodfor presulfiding hydroprocessing catalyst in order to improveoperability, reduce catalyst fouling rate, and extend the catalytic lifeof a catalyst bed employed in a hydroconversion reaction zone duringhydroprocessing. The present invention more particularly furtherprovides for a method for presulfiding hydroprocessing catalyst ex-situbefore transferring presulfided hydroprocessing catalyst into ahydroprocessing reactor system. The method is intended to improve theoperability and reduce catalyst fouling rate, and to extend thecatalytic life of a generally “packed catalyst bed” in thehydroprocessing reactor system that is preferably capable of onstreamcatalyst replacement. The methods of the present invention may also beadvantageously practiced in hydrocarbon reactor systems that utilize an“expanded catalyst bed”, such as the ebullated beds as described in U.S.Pat. No. 4,571,326 and U.S. Pat. No. 4,744,887.

[0003] The following three acceptable reactor technologies are currentlyavailable to the industry for hydrogen upgrading of “heavy” hydrocarbonliquid streams: (i) fixed bed reactor systems; (ii) ebullated orexpanded type reactor systems which are capable of onstream catalystreplacement and are presently known to industry under the trademarksH-Oil_(R) and LC-Fining_(R); and (iii) the substantially packed-bed typereactor system having an onstream catalyst replacement system, as moreparticularly described in U.S. Pat. No. 5,076,908 to Stangeland et al,having a common assignee with the current inventions and discoveries. Afixed bed reactor system may be defined as a reactor system having oneor more reaction zone(s) of stationary catalyst, through which feedstreams of liquid hydrocarbon and hydrogen flow downwardly andconcurrently with respect to each other. An ebullated or expanded bedsystem may be defined as a reactor system having an upflow type singlereaction zone reactor containing catalyst in random motion in anexpanded catalytic bed state, typically expanded from 10% by volume toabout 35% or more by volume above a “slumped” bed level which is thevolume of a catalytic bed in an ebullated reactor system in anon-expanded or non-ebullated state and without a hydrocarbon streamupflowing therethrough. As particularly described in U.S. Pat. No.5,076,908 to Stangeland et al, the substantially packed-bed type reactorsystem is an upflow type reactor system including multiple reactionzones of packed catalyst particles having little or no movement duringnormal use under conditions of no catalyst addition or withdrawal. Inthe substantially packed-bed type reactor system of Stangeland et al,when catalyst is withdrawn from the reactor during normal catalystreplacement, the catalyst flows in a downwardly direction underessentially plug flow or in an essentially plug flow fashion, with aminimum of mixing with catalyst in layers which are adjacent eitherabove or below the catalyst layer under observation. It is well known tothose skilled in the art of hydrogen upgrading of heavy hydrocarbonliquid streams that catalyst utilized for hydrodemetallation,hydrodesulfirization, hydrodenitrogenation, hydrocracking, etc., ofheavy oils and the like are generally made up of a carrier of basematerial, such as alumina, silica, silica-alumina, or possibly,crystalline aluminosilicate, with one or more promoter(s) orcatalytically active metal(s) (or compound(s)) plus trace materials.Typical catalytically active metals utilized are cobalt, molybdenum,nickel and tungsten; however, other metals or compounds could beselected dependent on the application. It is also well know to thoseskilled in the art of upgrading of heavy oils that potential catalystactivity and useful life can be substantially influenced by the mannerin which fresh catalyst is prepared and/or conditioned prior to beingexposed to normal reactor operating conditions. More specifically,promoter or catalytically active metals contained in fresh catalyst arein an oxide state. During use for hydroprocessing a sulfur containingfeed, the metal oxides are converted to metal sulfides. Catalyticperformance of these metal sulfides is generally improved when theoxides in the fresh catalyst are converted to sulfides prior to exposureto reactor operating conditions, using a process termed catalystpresulfiding. Specific procedures have been developed over time by thoseinvolved in the industry to presulfide the fresh catalyst charges offixed bed type reactor systems in-situ at the start of each run. Theseprocedures normally involve a gas heatup and catalyst drying procedureof catalyst in the reactor vessel, followed by catalyst wetting/soakingwith startup oil, and then subsequently proceeding to a sulfiding stepthat employs either non-spiked feedstock (a feedstock containingnaturally occurring sulfur compounds) and a sulfur spiked feedstock (afeedstock to which sulfur compounds are added). The sulfiding (orpresulfiding) step may also and alternatively employ H₂/H₂S for vaporphase sulfiding. The techniques, as well as several other approaches,are presented and discussed in a technical paper by Harman Hallie at acatalyst symposium in Amsterdam, May 1982, and printed in the Dec. 20,1982 issue of Oil and Gas Journal, and in another paper presented byWilliam J. Tuzynski, at the 1989 NPRA Meeting, and entitled Propertiesand Application of Commercial Presulfiding Agents.

[0004] Generally, non-spiked feedstock presulfiding techniques involvedecomposition of sulfur compounds, which are naturally present in aselected startup hydrocarbon feed, into H₂S at reactor temperatureconditions ranging from about 300° C. (572° F.) to about 350° C. (662°F.). Spiked feedstock presulfiding techniques are carried out byinjecting sulfur-containing organic compounds into a selected startuphydrocarbon feed such that the injected sulfur-containing organic maydecompose into H2S at temperatures lower than temperatures required todecompose the naturally occurring sulfur compounds present in thestartup oil feedstock. Spiking agents currently preferred by theindustry are dimethylsulfide (DMS) and dimethyldisulfide (DMDS) whichallow sulfiding procedures to be accomplished typically at temperaturesin the range of from about 250° C. to about 275° C. Vapor phasepresulfiding is difficult to control and, in general, does not achievethe optimum results in commercial applications, due to several reasonsincluding poor distribution and uneven sulfiding, poor heat sink ofexothermic reactions, etc.

[0005] Techniques have been developed in which catalyst is pretreated byimpregnation with a sulfur compound (e.g. a polysulfide) before beingcharged to a reactor for so-called ex-situ presulfiding; however, thecatalyst must still undergo drying, wetting, and conversion in-situ froma metal oxide state to a metal sulfide state within the reactor duringstartup procedures. In this case, the major benefit claimed is reducedstartup time and potentially improved activity. U.S. Pat. No. 4,576,710suggests presulfiding regenerated catalyst for use in an ebullating bedreactor, but provides no disclosure of the mechanical details oroperating practice to make such a presulfiding step functional.

[0006] Conventional presulfiding and startup procedures are tailored tomaintain startup oil feed quality and reactor temperature conditionssuch that the sulfiding and hydrogenation reactions do not createdeleterious temperature conditions in the interior of catalyst pelletsthat result in either carbon deposition or metal sintering, both ofwhich reduce catalyst activity. Simply stated, the severity ofhydrogenation reactions during the initial catalyst conditioning andsulfiding period is limited by startup oil quality (e.g. sulfur content)and reactor temperature conditions until the sulfiding reactionsdiminish or essentially stop. Present-day state-of-the-art techniquesallow in-situ presulfiding to be initiated at temperatures below about200° C. (392° F.) and completed before temperatures are elevated aboveabout 300° C. (572° F.). Harman Hallie's technical paper in the Dec. 20,1982 issue of Oil and Gas Journal indicates catalyst activitydifferences or reductions of from 7% to about 33% could be experience ifsulfiding is carried out at higher temperature conditions. Such activitylosses may occur when fresh or regenerated catalyst batches withpromoter metal in an oxide state are suddenly loaded into an onstreamreactor operating at temperatures in excess of 300° C. Therefore, whatis needed and what has been invented by us is a viable, reasonablyachievable and economical method for presulfiding fresh batches ofcatalyst which are to be added to an onstream reactor operating atelevated temperatures and hydrogen pressures. A substantial benefit canbe gained from preconditioning fresh or regenerated catalyst in order toconvert a major portion of the promoter metal oxide into the metalsulfide state prior to its being loaded into an onstrearn reactoroperating at elevated temperatures and hydrogen pressures.

[0007] A technical bulletin published by Criterion Catalyst Company,LLP, entitled ¹“Criterion Hydrotreating Catalysts PresulfidingProcedures”, discusses means of maximizing catalyst activity inhydrotreating applications by presulfiding the catalyst. Enhancement ofactivity and enhancement of cycle length are different concepts. Thereis no discussion of means to enhance catalyst cycle length bypresulfiding the catalyst in this reference or in the other referencesdisclosed in the specification. Furthermore, this publication does notdiscuss presulfiding catalyst for use in hydroprocessing of “heavy”hydrocarbon liquid streams, such as atmospheric residuum.

SUMMARY OF THE INVENTION

[0008] The present invention is directed to a process for presulfiding ahydrocarbon conversion catalyst for use in a moving bed reactor whichcomprises at least one reaction zone containing catalytic particulates.Included in the moving bed reactor are means for removing catalyticparticulates from the reaction zone and means for adding catalyticparticulates to the reaction zone while maintaining the reaction zone ata temperature and at a pressure selected for hydroconverting a refinerystream. During the hydroconversion process, a refinery stream incombination with added hydrogen gas is contacted over catalyticparticulates within the reaction zone for removing contaminants from therefinery stream, including one or more of nitrogen, sulfur, aromaticsand metals. The effluent from the reaction zone is therefore reduced inone or more of the contaminants relative to the feedstock to thereaction zone.

[0009] It is a feature of the moving bed reactor that at least a portionof the catalytic particulates may be removed from the reaction zoneduring hydroconversion, and further catalytic particulates may be addedto the reaction zone during hydroprocessing. Being able to add andremove catalytic particulates without the need for shutting down thereaction process permits the operator to quickly tailor a bed ofcatalytic particulates for achieving a desired product slate or catalystactivity without the burden of a complete reactor shutdown to replacecatalyst. The moving bed reactor also permits the operator to convertrefinery streams, such as metals containing streams, which wouldotherwise quickly deactivate a catalyst. Frequent shutdowns to removemetal fouled catalyst is a major expense for operators of conventionalfixed bed hydroconversion processes.

[0010] In its broadest aspect, the present invention is directed to aprocess for hydroprocessing a hydrocarbon feed stream that is upflowingthrough a hydroconversion reaction zone, the process comprising:

[0011] introducing a hydrocarbon feed stream in the presence of hydrogenat a reaction pressure into a hydroconversion reaction zone whichcontains particulate hydroprocessing catalyst to commence upflowing ofsaid hydrocarbon feed stream through said catalyst and to recover areaction effluent therefrom;

[0012] sulfiding a volume of hydroprocessing catalyst within a treatmentzone to produce sulfided catalyst; and

[0013] adding at least a portion of the sulfided catalyst into thehydroconversion reaction zone while maintaining the reaction zone at thereaction pressure.

[0014] The preferred treatment zone for the catalyst sulfiding systemcomprises one or more treatment vessels which are separate from thehydroconversion reaction zone contained in the reactor vessel. Typicalsulfiding temperatures range from 90° C. to 370° C. The preferredtemperature for sulfiding the catalytic particulates is in the rangefrom 125° C. to 325° C. The preferred pressure is in the range from 200KPa (15 psig) up to or slightly above (e.g. less than 450 KPa or 50 psigabove) the pressure of the reaction zone .

[0015] An important aspect of the present invention is the method ofpreparing and use of a presulfided catalyst in a moving bed reactionsystem. In conventional fixed bed processes, fresh catalyticparticulates are generally sulfided in the reaction vessel prior to theintroduction of a refinery stream for reaction. In reaction systemspermitting catalyst addition during hydroprocessing, fresh catalysts areconventionally added in an unsulfided state to the reaction zone, andare sulfided by the sulfur compounds present in the fluids flowingthrough the catalytic particulates during reaction. However, the needfor more hydroconversion activity while processing heavy feeds hasresulted in the use of catalysts which benefit from careful sulfidingprior to exposure to the heavy feeds at reaction conditions. Accordingto the present invention, an embodiment for sulfiding the volume ofhydroprocessing catalyst within the treatment zone comprises the stepsof:

[0016] adding a volume of hydroprocessing catalyst to the treatmentzone, which volume includes fresh hydroprocessing catalyst;

[0017] heating the volume of hydroprocessing catalyst until the catalysthas a temperature ranging from 90° C. to 370° C.; and

[0018] adding a sulfiding agent to the treatment zone to preparesulfided catalyst. In the preferred process of the invention, the methodof adding the volume of hydroprocessing catalyst to the treatment zonecomprises the steps of:

[0019] preparing a slurry comprising a hydrocarbon liquid and a volumeof hydroprocessing catalyst;

[0020] adding the slurry comprising the hydrocarbon liquid and thehydroprocessing catalyst to the treatment zone; and

[0021] removing at least a portion of the hydrocarbon liquid from thetreatment zone. and the method of adding a sulfiding agent to thetreatment zone comprises:

[0022] pressurizing the treatment zone which contains thehydroprocessing catalyst with a sulfiding agent at a pressure in therange of 0.2 to 24.2 MPa and a temperature in the range of 90° C. to370° C. to produce at least partially sulfided catalyst; and

[0023] removing at least a portion of the sulfiding agent from thetreatment zone.

[0024] In a further embodiment of the invention, the process forsulfiding the catalyst in the treatment zone includes flowing a fluidcomprising the sulfiding agent through the catalyst within the treatmentzone, in a process comprising:

[0025] adding a volume of hydroprocessing catalyst to the treatmentzone, which volume includes fresh hydroprocessing catalyst;

[0026] flowing a heated hydrocarbon liquid through the volume ofhydroprocessing catalyst within the treatment zone until the catalysthas a temperature ranging from 90° C. to 145° C.;

[0027] subsequently pressurizing the treatment zone at a pressureranging from 0.2 MPa to 24.2 MPa (15-3500 psig);

[0028] continuing to flow the heated hydrocarbon liquid through thecatalyst in the treatment zone until the catalyst has a temperatureranging from 90° C. to 370° C.;

[0029] flowing a sulfiding mixture through the catalyst in the treatmentzone to prepare at least partially sulfided catalyst.

[0030] The preferred temperature for sulfiding the catalyticparticulates is in the range from 125° C. to 325° C. The preferredpressure is in the range from 200 KPa (15 psig) up to or slightly above(e.g. less than 450 KPa or 50 psig above) the pressure of the reactionzone.

[0031] The presulfided catalyst produced in the process is added to ahydroconversion reaction zone while maintaining the reaction zone at asuitable reaction pressure according to the following:

[0032] adding a hydrocarbon liquid to the sulfided catalyst in thetreatment zone;

[0033] forming a slurry comprising the hydrocarbon liquid and at least aportion of the sulfided catalyst; and

[0034] adding the slurry of the hydrocarbon liquid and the sulfidedcatalyst to the hydroconversion reaction zone while maintaining thereaction zone at the reaction pressure.

[0035] In a more preferred embodiment, the present invention is directedto a moving bed reaction zone with a substantially packed bed ofcatalyst. A method for hydroprocessing a hydrocarbon feed stream that isupflowing through a hydroconversion reaction zone having a substantiallypacked bed of catalyst comprises the steps of:

[0036] introducing a hydrocarbon feed stream into a hydroconversionreaction zone having a substantially packed bed of particulatehydroprocessing catalyst to commence upflowing of said hydrocarbon feedstream through said substantially packed bed of the catalyst at a rateof flow such that said substantially packed bed of hydroprocessingcatalyst expands to less than 10% by length beyond a substantially fullaxial length of said substantially packed bed of hydroprocessingcatalyst in a packed bed state, and to recover a reaction effluenttherefrom;

[0037] withdrawing a first volume of the hydroprocessing catalyst fromthe hydroconversion reaction zone to commence essentially plug-flowingdownwardly said substantially packed bed of hydroprocessing catalystwithin said hydroconversion reaction zone;

[0038] adding a second volume of a particulate hydroprocessing catalystto a treatment zone, which second volume includes fresh hydroprocessingcatalyst;

[0039] sulfiding the second volume of hydroprocessing catalyst withinthe treatment zone to prepare sulfided catalyst; and

[0040] adding at least a portion of the sulfided catalyst into thehydroconversion reaction zone to replace the withdrawn first volume ofcatalyst.

[0041] The present invention is directed to presulfiding ahydroprocessing catalyst prior to adding the catalyst to ahydroconversion reaction zone. Processes taught in the art sulfide thehydroprocessing catalyst in situ, by adding fresh, unsulfided catalystto the catalyst bed for sulfiding the catalyst using sulfur-containingreactants which pass through the fresh, unsulfided catalyst. Generally,these prior art sulfiding processes are also run at temperature rangeswhich are higher than those employed in the present process. Among otherfactors, the present invention is based on the surprising discovery thatcatalysts which are presulfided according to the present processdemonstrate substantially higher performance when used forhydroconversion. The present method provides for sulfiding catalyst,using sulfur compounds present in product streams from thehydroconversion process, at low sulfiding temperatures for preparing acatalyst which has higher performance in catalyzing conversionreactions, particularly desulfurization reactions, of heavy feeds. Thisdiscovery is particularly important for operating moving bed reactors,and in particular reactors operating with substantially packed bedupflow reactors under plug flow conditions during catalyst addition andwithdrawal.

In the Figures

[0042]FIG. 1 illustrates an embodiment of the invention with a highpressure catalyst transfer vessel only for presulfiding the catalystaccording to the invention.

[0043]FIG. 2 illustrates an embodiment of the invention with a lowpressure catalyst transfer vessel and a high pressure catalyst transfervessel for presulfiding the catalyst according to the invention.

[0044]FIG. 3 shows the improved desulfurization performance of acatalyst presulfided according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0045] Referring in detail now to FIGS. 1, 2 for preferred embodimentsof the present invention, there is seen a catalyst presulfiding systemin communication with the catalyst bed 10 of the reactor vessel 11. Thecatalyst sulfiding system functions for sulfiding catalyst (i.e. theconverting of metallic oxide(s) within the catalyst into metallicsulfide(s)) before the catalyst is introduced into the reactor vessel11. In the invention, catalyst is sulfided (i.e. presulfided) in one ormore vessels within treatment zone 50.

[0046] The reaction zone 10 contained within reactor vessel 11 ispreferably an upflow reaction system, with reacting fluids enteringreaction zone 10 through feed inlet 14, passing upward in upflow modethrough reaction zone 10 moving bed reactor, the reaction effluentexiting through conduit 16. The catalyst presulfiding process iseffective for reaction zones operated as a ebullating bed reactionsystem or as a substantially packed-bed type reactor system having anonstream catalyst replacement system (i.e. having a capability fortransferring catalyst to and from the reaction zone at substantiallyreaction pressure). To maintain the reactor system as a substantiallypacked-bed type reactor system, the onstream catalyst replacement systemis a counterflow processing system where the catalyst and fluid velocitycombinations limit bed expansion to less than 10% by length beyond asubstantially full axial length of the bed in a packed bed state. It ismore preferred that the bed expansion be maintained at less than 5% andmore preferred at less than 1% of the substantially full axial length ofthe bed in a packed bed state. A preferred substantially packed bed typereactor system is taught in U.S. Pat. No. 5,076,908 the disclosure ofwhich is incorporated herein by reference for all purposes.

[0047] In the embodiment of the invention depicted in FIG. 1, thecatalyst sulfiding system comprises catalyst transfer vessel 304 incommunication with catalyst loading hopper 312 for accepting anddispensing hydroprocessing catalyst. Catalyst hopper 312 has a dependingconduit 314 communicating therewith and with the high pressure catalystfeed vessel 304 for conducting hydroprocessing catalyst from thecatalyst loading hopper 312 to the catalyst feed vessel 304. Thedepending conduit 314 is conveniently provided with a valve 318 forregulating catalyst flow therethrough. Catalyst is preferablytransferred from catalyst loading hopper 312 to catalyst feed vessel 304as a slurry in a hydrocarbon oil.

[0048] In one embodiment of the invention, the hydroprocessing catalystto be sulfided within the catalyst transfer vessel 304 is treating witha sulfiding agent. The “spiking” or sulfiding agent may be any suitablespiking or sulfiding agent (e. g. mercaptan compounds, thiopheniccompounds, organosulfides, etc.) but is preferably a sulfur rich recyclestream recovered from the reaction effluent. Sulfur containingmaterials, such as dimethyldisulfide or dimethylsulfide, may also beused. An example sulfiding agent is a hydrocarbon gas (e. g. methane,ethane, or the like, etc.) that is rich in hydrogen sulfide (H₂S),preferably containing from about 5% by weight to about 80% by weightH₂S. When H₂S is employed as a sulfiding agent in the present process, apreferred H₂S is derived from a recycle stream (not shown) recoveredfrom the reaction effluent 16. For example, the reaction effluent 16 maybe separated into two or more components by boiling point. Furtherseparations may produce a H₂S rich stream, which may be recycled viaconduit 328 for use as a sulfiding agent.

[0049] As already stated, the catalyst may be transferred from thecatalyst hopper 312 to the catalyst transfer vessel 304 in a slurry,where the liquid component of the slurry may be a product stream fromthe process, such as a flush oil. At least a portion of the oilremaining in the catalyst transfer vessel following transfer of catalystfrom the catalyst hopper to the catalyst transfer vessel ispreferentially drained from the catalyst transfer vessel prior tointroduction of the sulfiding agent, through conduit 310, in cooperationwith valve 311. In the embodiment shown in FIG. 1, sulfiding agent maybe introduced to the catalyst transfer vessel through conduit line 212in cooperation with valve 213, or through conduit line 328, incooperation with valve 330.

[0050] Prior to sulfiding, the catalyst is heated to an elevatedtemperature, such as from 50° C. to 370° C., more preferably from 125°C. to 325° C., still more preferably from 150° C. to 285° C. The heatmay be supplied by the catalyst transfer vessel, heated to an elevatedtemperature, such as between 90° C. and 370° C., using an externalheating source, such as a steam jacket. Alternatively, the catalyst maybe heated prior to addition of catalyst to the transfer vessel, or byusing a heated liquid for flowing through the catalyst in the transfervessel. In the embodiment of FIG. 1, heated hydrocarbon oil may besupplied from flush oil drum, generally illustrated as 356, throughconduit 340, where the heated oil is supplied to the flush oil drumthrough conduit 354, in cooperation with valve 356. The “hydrocarbon”(e.g. a gas oil or a flushing oil) for the heated hydrocarbon and thecold hydrocarbon may be any suitable hydrocarbon but is preferably aheavy distillate fraction boiling above 315 ° C. and more preferablyboiling in the range of from 315° C. to 525° C. It will be apparent toone skilled in the art, however, that hydrocarbon oils boiling belowthat immediately specified will be suitable in the subject preferredembodiment, so long as the oil does not vaporize to any significantextent at sulfiding conditions during the sulfiding process in the highpressure catalyst transfer vessel 304.

[0051] In this preferred embodiment, catalyst transfer vessel 304, withadded catalyst from which at least a portion of the liquid oil used fortransporting the catalyst from catalyst hopper 312 is removed, ispressurized with an H₂S containing stream. The H₂S containing stream canbe at any pressure from ambient pressure up to the pressure withinreactor vessel 11, such as from 0.2 MPa to 24.2 MPa (15-3500 psig). H₂Scontained in a recycle stream will generally have a pressure of from 0.2MPa to 3.4 MPa (15-500 psig). The sulfiding agent is introduced to thecatalyst transfer vessel through either conduit 212 or conduit 328, andvalves associated with conduits leading to the catalyst transfer vesselblocked closed, including valves 307, 311, 323, 318, and 386. Valve 213remains open, and the catalyst transfer vessel is pressurized to thedesired pressure, including up to the pressure of the reactor vessel,using hydrogen or a gaseous mixture containing hydrogen, through conduit212. At the desired pressure, valve 213 is closed for a time sufficientto sulfide the catalyst in the transfer vessel. During sulfiding, thecatalyst is maintained at a temperature in the range of 90° C.-370° C.,preferably in the range 125° C.-325° C., more preferably in the range of150° C.-285° C., and still more preferably in the range of 175° C.-240°C. Generally, less than 24 hours, preferably less than 10 hours, morepreferably less than 5 hours is sufficient to at least partially sulfidethe catalyst. The presulfiding process results in sulfiding at least 35%and more preferably at least 50% of the stoichiometric amount of metaloxide sites available on the catalyst. It may be desirable to furthersulfide the catalyst with additional treatments of the sulfiding agent.Additional treatments beyond the first are performed in essentially thesame way as the first treatment. Thus, at the end of the firsttreatment, the catalyst transfer vessel 304 is depressurized, forexample through conduit 212, and additional sulfiding agent is added tothe transfer vessel 304. As before, the vessel is pressurized with H₂ tothe desired pressure, and the catalyst sulfided under pressure forgenerally less than 24 hours, preferably less than 10 hours, morepreferably less than 5 hours. It will be clear to the skilledpractitioner that a tradeoff will exist between the concentration of theactive sulfur-containing material, such as H₂S, in the sulfiding agent,the pressure employed during sulfiding the time that sulfiding ispermitted to take place and the number of sulfiding cycles employed.Greater amounts of sulfiding will be expected at high concentrations ofthe sulfur containing material, at higher pressures in the sulfidingstep, or for processes in which the sulfiding step is conducted for alonger time. The choice of concentration, pressure and time is largely amatter of local conditions; all combinations are to be considered to bewithin the bounds of the claimed invention, so long as the sulfidedcatalyst retains a measurable amount of sulfur at the conclusion of thesulfiding process.

[0052] Sulfided catalyst which is sulfided in catalyst transfer vessel304 is generally transported to reactor vessel 10 in a slurry with ahydrocarbon oil. Such oil may be supplied from flush oil drum 356through conduit 340. It is desirable that the catalyst be passed to thereactor in a heated state, e.g. 125-325° C., and so heated oil fromflush oil drum 356 is generally used. Such oil may be supplied thoughhot oil supply line 354 in quantities sufficient to immerse at least aportion of the catalyst in oil at a pressure equal to or slightly higherthan the pressure in the reactor vessel. Valve 307 is then opened andthe catalyst is passed into the reactor vessel at a rate determined bythe rate of oil addition via conduit 324 to the catalyst transfer vessel304.

[0053] In a separate embodiment, catalyst in transfer vessel 304 issulfided using a sulfiding agent which is flowed through the catalyst inthe transfer vessel 304 during the sulfiding process. Either gaseous orliquid sulfiding agents may be used. As before, catalyst loading hopper312 is provided for accepting and dispensing hydroprocessing catalystwhich preferably comprises the catalyst of the present invention. Thecatalyst loading hopper 312 has a depending conduit 314 communicatingtherewith and with the high pressure catalyst feed vessel 304 forconducting hydroprocessing catalyst from the catalyst loading hopper 312to the catalyst feed vessel 304. The depending conduit 314 isconveniently provided with a valve 318 for regulating catalyst flowtherethrough. The high pressure catalyst feed vessel 304 is providedwith a high pressure feed conduit 324 with valve 323 for conducting afeed stream into the high pressure catalyst feed vessel 304.

[0054] The high pressure feed conduit 324 communicates with various feedstreams that emanate from various conduits. Conduit 328 conducts a“spiking” or sulfiding agent into the high pressure feed conduit 324.Flow control valve 330 controls the flow of “spiking” or sulfiding agentin the sulfiding system. Conduit 340 conducts a heated hydrocarbon (e.g.a hot gas oil) and is capable of feeding the high pressure feed conduit324. Line 340 includes flow control valve 348 for controlling the flowof heated hydrocarbon for admixing as desired in the feed conduit 324with the “spiking” or sulfiding agent originating from conduit 328.Conduit 350 contains a flow/liquid level control valve 360 and functionsfor transporting a cold hydrocarbon (e.g. a cold gas oil) to a flush oildrum, generally illustrated as 356. Line 362 contains a flow controlvalve 358 and interconnects the sulfiding system and the conduit 350 fordispensing a cold hydrocarbon from conduit 350 into the sulfiding feedconduit 324 for admixing with the “spiking” or sulfiding agent and theheated hydrocarbon for lowering the overall temperature of a sulfidingagent/heated hydrocarbon mixture, or for flushing or washing through acatalytic bed (not shown) within the high pressure catalyst feed vessel304 after the catalyst has been presulfided. In a preferred embodiment,the hydroprocessing catalyst is heated by flowing a heated hydrocarbonliquid through the volume of hydroprocessing catalyst within thetreatment zone 50 until the catalyst has a temperature ranging from 90°C. to 145° C. The treatment zone is subsequently pressurizing at apressure ranging from 0.2 MPa to 24.2 MPa (15-3500 psig), and heatedhydrocarbon liquid is continued to flow through the catalyst in thetreatment zone until the catalyst has a temperature ranging from 125° C.to 325° C. A sulfiding mixture, delivered via conduit 324 is then flowedthrough the catalyst in the treatment zone to prepare sulfided catalyst.

[0055] The high pressure catalyst feed vessel 304 is formed with ascreen 382 in communication with a conduit 384. Any mixture of heatedhydrocarbon and/or cold hydrocarbon and residual (unreacted) “spiking”or sulfiding agent overflowing the high pressure catalyst feed vessel304 passes through screen 382 and into the conduit 384 fortransportation to and dispensing into a flush oil separator 376. Conduit384 comprises a flow/pressure control valve 386 for controlling mixtureflow through conduit 384 and for controlling operating or workingpressures within the high pressure catalyst feed vessel 304.

[0056] The flush oil separator 376 separates any mixture of heatedhydrocarbon and/or cold hydrocarbon and residual (unreacted) “spiking”or sulfiding agent into various components. In a preferred embodiment ofthe invention where the “spiking” or sulfiding agent is an H₂S-richhydrocarbon gas, the flush oil separator 376 separates mixture(s) ofheated hydrocarbon and/or cold hydrocarbon and H₂S-rich hydrocarbon gasinto an overhead gas (e.g. methane, ethane, nitrogen, etc. and mixturesthereof), which exits through an exit conduit 396, having flow/pressurecontrol valve 398, and a recovered liquid hydrocarbon which exits theflush oil separator 376 through an exit conduit 390 that extends fromthe flush oil separator 376 to conduit 352 where the recovered liquidhydrocarbon is mixed with heated hydrocarbon and/or cold hydrocarbon forintroduction into the flush oil drum 356. A liquid/flow control valve392 in exit conduit 390 controls the flow of recovered liquidhydrocarbon from the flush oil separator 376 through the exit conduit390.

[0057] The recovered liquid hydrocarbon from the flush oil separator 376typically contains residual overhead gas that did not separate out inthe flush oil separator 376. In those typical occurrences, when amixture of recovered liquid hydrocarbon and heated hydrocarbon and/orcold hydrocarbon is introduced into the flush oil drum 356 from conduit352, residual overhead gas separates in the flush oil drum 356 from themixture and is dispensed through a conduit 414. Conduit 414 contains aflow/pressure control valve 420 for regulating residual overhead gasflow and for regulating working or operating pressures within the flushoil drum 356.

[0058] In the embodiment of the invention depicted in FIG. 2, thetreatment zone for the catalyst sulfiding system comprises two vesselswhich are separate from the hydroconversion reaction zone contained inthe reactor vessel, a low pressure catalyst feed vessel, generallyillustrated as 302, communicating with a high pressure catalyst transfervessel, generally illustrated as 304, via a conduit 306 having a valve308 for controlling the transfer of at least partially sulfided catalystfrom the low pressure catalyst feed vessel 302 to the high pressurecatalyst transfer vessel 304. In this embodiment of the invention, thelow pressure catalyst feed vessel 302 is provided as an initial vehiclefor wetting, preheating, and at least partially presulfiding thehydroprocessing catalyst before the transfer of at least partiallypresulfided hydroprocessing catalyst from the low pressure catalyst feedvessel 302 through conduit 306 and into the high pressure catalysttransfer vessel 304. As will be readily apparent from the followingdescription, the high pressure catalyst transfer vessel 304 is providedwith sources for continuing to wet, preheat and further sulfide the atleast partially presulfided hydroprocessing catalyst, but at highertemperatures and/or pressures which approximate reaction conditionswithin the reactor vessel 11. Presulfiding of hydroprocessing catalystis performed at lower temperatures and pressures than temperatures andpressures required for directly transferring presulfided catalyst into ahydroconversion reaction zone such as that existing within the reactorvessel 11. Example sulfiding conditions in the low pressure catalysttransfer vessel 302 include a pressure of greater than 200 KPa (15psig), preferably between 200 KPa and 7000 KPa (15 psig and 1000 psig),and a temperature of 90° C. to 370° C. It is to be understood that thespirit and scope of the present invention as depicted in FIG. 1 includesdisposing fresh (to be sulfided) hydroprocessing catalyst in both thelow pressure catalyst feed vessel 302 and the high pressure catalysttransfer vessel 304, and subsequently sulfiding simultaneously bothbatches of hydroprocessing catalyst positioned in the two vessels 302and 304.

[0059] Sulfided catalyst passes from the high pressure catalyst transfervessel 304 through conduit 305 for deposit into the reactor vessel 11.The conduit 305 contains a block valve 307. A catalyst loading hopper312 is provided for accepting and dispensing hydroprocessing catalystwhich preferably comprises the catalyst of the present invention. Thecatalyst loading hopper 312 has a depending conduit 314 communicatingtherewith and with the low pressure catalyst feed vessel 302, or withthe high pressure catalyst feed vessel 304 for conductinghydroprocessing catalyst from the catalyst loading hopper 312 to thecatalyst feed vessels 302 or 304. The depending conduit 314 isconveniently provided with a valve 318 for regulating catalyst flowtherethrough. The low pressure catalyst feed vessel 302 is provided witha low pressure feed conduit 320 with associated valve 321 for conductinga feed stream into the low pressure catalyst feed vessel 302. A highpressure feed conduit 324 communicates with the high pressure catalysttransfer vessel 304 for furnishing a feed stream that is to upflowtherethrough.

[0060] The low pressure feed conduit 320 and the high pressure feedconduit 324 communicate with various feed streams that emanate fromvarious conduits. Conduit 328 conducts a “spiking” or sulfiding agentinto the low pressure feed conduit 320 and the high pressure feedconduit 324 via line 329. Flow control valve 330 controls the flow of“spiking” or sulfiding agent in the sulfiding system. Conduit 340conducts a heated hydrocarbon (e.g. a hot gas oil) and is capable offeeding the low pressure feed conduit 320 and the high pressure feedconduit 324 through line 329. Line 340 includes flow control valve 348for controlling the flow of heated hydrocarbon for admixing as desiredin the feed conduits 320 and 324 respectively with the spiking” orsulfiding agent originating from conduit 328. Conduit 350 contains aflow/liquid level control valve 360 and functions for transporting acold hydrocarbon (e.g. a cold gas oil) to a flush oil drum, generallyillustrated as 356. Line 362 contains a flow control valve 358 andinterconnects the sulfiding system and the conduit 350 for dispensing acold hydrocarbon from conduit 350 into the sulfiding feed conduit 329for admixing with the sulfiding agent and the heated hydrocarbon forlowering the overall temperature of a sulfiding agent/heated hydrocarbonmixture, or for flushing or washing through a catalytic bed (not shown)within the low pressure catalyst feed vessel 302 and/or the highpressure catalyst feed vessel 304 after the catalyst has beenpresulfided. Another feature of the invention depicted in FIG. 2 is thatfresh (to be sulfided) hydroprocessing catalyst may be dispensed intoboth the low pressure catalyst feed vessel 302 and the high pressurecatalyst transfer vessel 304 and subsequently simultaneously sulfided inthe two vessels 302 and 304. Such positioning of fresh (to be sulfided)hydroprocessing catalyst may be accomplished in any suitable manner suchas initially adding a batch of fresh (to be sulfided) hydroprocessingcatalyst into the low pressure catalyst feed vessel 302 from thecatalyst loading hopper 312 and subsequently transferring via conduit306 such initially added batch of fresh hydroprocessing catalyst to thehigh pressure catalyst transfer vessel 304 and refilling the lowpressure catalyst feed vessel 302 from the catalyst loading hopper 312with another batch of fresh (to be sulfided) hydroprocessing catalyst.Alternatively, a second catalyst loading hopper (not shown) may beprovided and dedicated to the high pressure catalyst transfer vessel 304for dispensing fresh (to be sulfided) hydroprocessing catalyst directlyinto the high pressure catalyst transfer vessel 304 instead of throughthe low pressure catalyst feed vessel 302. If two batches ofhydroprocessing catalyst are to be sulfided simultaneously in vessels302 and 304, flow control valves 330, 348, 358, and in lines 328, 340,362, respectively, are all opened and regulated as necessary and aswould be well known to artisans in the art such that mixtures ofsulfided agent and heated hydrocarbon and/or cold hydrocarbon areintroduced simultaneously into conduits 320 and 324 for simultaneousupflow through fresh (to be sulfided) hydroprocessing catalyst that hasbeen previously positioned in vessels 302 and 304.

[0061] The low pressure catalyst feed vessel 302 is formed with a screen370 in communication with a conduit 372. Any mixture of heatedhydrocarbon and/or cold hydrocarbon and residual (unreacted) “spiking”or sulfiding agent overflowing the 5 low pressure catalyst feed vessel302 passes through screen 370 and into the conduit 372 fortransportation to and dispensing into a flush oil separator 376. Conduit372 comprises a flow/pressure control valve 380 for controlling mixtureflow through conduit 372 and for controlling operating or workingpressures within the low pressure catalyst feed vessel 302. The highpressure catalyst transfer vessel 304 is formed with a screen 382wherethrough any mixture of heated hydrocarbon and/or cold hydrocarbonand residual (unreacted) “spiking” or sulfiding agent may pass and beintroduced into a conduit 384 for transportation through conduit 374 tothe flush oil separator 376. The conduit 384 contains a flow/pressurecontrol valve 386 for controlling mixture flow through conduit 384 fromthe high pressure catalyst transfer vessel 304 and for controllingoperating and working pressures within the latter.

[0062] Preferably, the sulfiding process conditions within the lowpressure catalyst feed vessel 302 include an operating pressure rangingfrom 0.7 KPa to 1480 KPa (0.1-200 psig) and an operating temperatureranging from 90° C. to 20 370° C.; more preferably an operating pressureranging from 200 KPa to 1140 KPa (15-150 psig) and an operatingtemperature ranging from 125° C. to 325° C. Sulfiding process conditionswithin the high pressure catalyst transfer vessel 304 include anoperating pressure ranging from 0.7 KPa to 24.2 MPa (0.1-3500 psig) andan operating temperature ranging from 90° C. to 370° C.; more preferablyan operating pressure ranging from 7.0 MPa to 24.2 MPa (1000-3500 psig)and an operating temperature ranging from 125° C. to 325° C.

[0063] In the process, presulfided catalyst from high pressure transfervessel 304 may be added to the hydroconversion reaction zone throughconduit 305. While not required, it may be desirable to remove a volumeof catalyst from the reaction zone 10, the volume removed beingapproximately equal to the volume of presulfided catalyst to be added tothe reaction zone 10. The order of operation, whether adding presulfidedcatalyst followed by removal of at least partially spent catalyst fromthe reaction zone, or, alternatively, removing at least partially spentcatalyst particulates from the reaction zone followed by addingpresulfided catalyst to the reaction zone, or, alternatively, removingat least partially spent catalyst particulates from the reaction zoneand adding presulfided catalyst particulates to the reaction zonesimultaneously, is not critical to the invention, so long as thecatalyst volume in the reaction zone does not exceed design capacity.Methods for transferring catalyst to and from a reaction zone which areuseful in the present process are disclosed, for example, in U.S. Pat.No. 5,498,327 the entire disclosure of which is incorporated herein byreference for all purposes.

[0064] The at least partially spent catalyst to be withdrawn from thehydroconversion reaction zone 10 is either intermittently orsemi-continuously or continuously withdrawn in the hydrocarbon liquid,as defined above, from the reactor vessel 11 and discharged into conduit198 via valve 94 for transfer to the high pressure catalyst recoveryvessel 304. The withdrawn catalyst will typically be from about 50% toabout 95% expended, more preferably from about 70% to about 80%expended, where a 100% presulfided expended catalyst will be fullyfouled and will possess essentially no useful hydroconversion activityat reaction conditions in the hydroconversion zone.

[0065] The at least partially spent catalyst in the hydrocarbon liquidhas a high concentration of catalyst to hydrocarbon liquid, preferablyfrom about 0.2 to about 1.0 pounds of particulate catalyst per pound ofcatalyst slurry (i.e. weight of withdrawn catalyst plus weight ofhydrocarbon liquids), more preferably from about 0.25 to about 0.8pounds of particulate catalyst per pound of catalyst slurry, mostpreferably about 0.5 pounds of particulate catalyst per pound ofcatalyst slurry. The hydrocarbon liquids may comprise a liquidhydrocarbon component which has not been converted (into lighterproducts) or partly converted or a mixture of partly converted andunconverted liquid hydrocarbon components or a mixture of ahydrogen-containing gas component and any of the liquid components.

[0066] In the preferred embodiment of a substantially packed catalystbed, the withdrawn at least partially spent catalyst is a volumetriclayer(i. e. the lowermost volumetric layer) of catalyst from thecatalyst bed 10 of reactor vessel 11. As withdrawal commences theparticulate catalyst in the catalyst bed 10 plug flows downwardly. Aspreviously indicated, the withdrawn at least partially expended catalystis transferred in the hydrocarbon liquid (as defined above) to the highpressure catalyst transfer vessel 304 as a concentrated highly denseliquid slurry in laminar flow, in order to avoid undue abrasion of thewithdrawn at least partially expended catalyst particles that are beingtransferred into the catalyst transfer vessel 304 by conduit 198.

[0067] Catalysts useful in the present process are described in detailin U.S. Pat. No. 5,472,928 the entire disclosure of which isincorporated herein by reference for all purposes. A preferred catalystcomprises an inorganic support which may include zeolites, inorganicoxides, such as silica, alumina, magnesia, titania and mixtures thereof,or any of the amorphous refractory inorganic oxides of Group II, III orIV elements, or compositions of the inorganic oxides. The inorganicsupport more preferably comprises a porous carrier material, such asalumina, silica, silica-alumina, or crystalline aluminosilicate.Deposited on and/or in the inorganic support or porous carrier materialis one or more metals or compounds of metals, such as oxides, where themetals are selected from the groups IB, VB, VIB, VIIB, and VIII of thePeriodic System. Typical examples of these metals are iron, cobalt,nickel, tungsten, molybdenum, chromium, vanadium, copper, palladium, andplatinum as well as combinations thereof. Preference is given tomolybdenum, tungsten, nickel, cobalt, platinum, and palladium andcombinations thereof. Suitable examples of catalyst of the preferredtype comprise nickel-tungsten, nickel-molybdenum, cobalt-molybdenum ornickel-cobalt-molybdenum deposited on and/or in a porous inorganic oxideselected from the group consisting of silica, alumina, magnesia,zirconia, thoria, boria or hafnia or compositions of the inorganicoxides, such as silica-alumina, silica-magnesia, alumina-magnesia andthe like.

[0068] The catalyst of the present invention may further compriseadditives, such as phosphorus, boron, clays (including pillared clays),boron phosphate or phosphor, and/or halogens, such as fluorine andchlorine. The boron phosphate compound may be present in an amountranging from about 10 to about 40 percent by weight calculated on theweight of the total catalyst (i.e. inorganic oxide support plus metaloxide(s)), and more preferably ranging from about 15 to about 30 percentby weight, whereas the halogens and phosphor are used in an amount ofless than about 10 percent by weight of the total catalyst.

[0069] Although the metal components (i.e. cobalt, nickel, molybdenum,etc.) may be present in any suitable amount, the catalyst of the presentinvention preferably comprises of from about 0.1 to about 60 percent byweight of metal component(s) calculated on the weight of the totalcatalyst (i.e. inorganic oxide support plus metal oxides) and morepreferably of from about 5 to about 50 percent by weight of the totalcatalyst. The metals of Group VIII are generally applied in a minorquantity ranging from about 0.1 to about 30 percent by weight, and themetals of Group VIB are generally applied in a major quantity rangingfrom about 1.25 to about 50 percent by weight. The atomic ratio of theGroup VIII and Group VIB metals may vary within wide ranges, preferablyfrom about 0.01 to about 15, more preferably from about 0. 05 to about10, and most preferably from about 0.1 to about 5.

[0070] The groups in the Periodic System referred to above are from thePeriodic Table of the Elements as published in Lange's Handbook ofChemistry (Twelfth Edition) edited by John A. Dean and copyrighted 1979by McGraw-Hill, Inc., or as published in The Condensed ChemicalDictionary (Tenth Edition) revised by Gessner G. Hawley and copyrighted1981 by Litton Educational Publishing Inc. In a more preferredembodiment for the catalyst, the oxidic hydrotreating catalyst or metaloxide component carried by or borne by the inorganic support or porouscarrier material is molybdenum oxide (MoO₃) or a combination of MoO₃ andcobalt oxide (CoO) or a combination of MoO₃ and nickel oxide (NiO) wherethe MoO₃ is present in the greater amount. The porous inorganic supportis more preferably alumina. The MoO₃ is present on the catalystinorganic support (alumina) in an amount ranging from about 1 to about60 percent by weight, preferably from about 1 to about 35 percent byweight, more preferably from about 2 to about 8 percent by weight basedon the combined weight of the inorganic support and metal oxide(s). WhenCoO (or NiO) is present it will be in amounts ranging up to about 30percent by weight, preferably from about 0.5 to about 20 percent byweight, more preferably from about 1 to about 6 percent by weight basedon the combined weight of the catalyst inorganic support and metaloxide(s). The oxidic hydrotreating catalyst or metal oxide component maybe prepared by depositing aqueous solutions of the metal oxide(s) on theporous inorganic support material and thoroughly drying, or suchcatalyst may be purchased from various catalyst suppliers. Catalystpreparative techniques in general are conventional and well known andcan include impregnation, mulling, co-precipitation and the like,followed by calcination.

[0071] In a preferred embodiment of the present invention, the catalystwill have a uniform size which is preferably spherical with a diameteras a mean of a normal Gausian distribution curve ranging from about{fraction (1/64)} inch to about ¼ inch, more preferably ranging fromabout {fraction (1/16)} inch to about ⅛ inch. To maintain a uniform sizeparticle, it is preferred that at least about 70%, preferably at leastabout 80%, and more preferably at least about 90% of the catalystparticles be of a size within about 20%, preferably within about 10%,and more preferably within about 5% of the mean catalyst particle size,where the mean particle size is based on the longest dimension of theparticle.

[0072] From the foregoing discussion it will be clear to the skilledpractitioner that, though the catalyst particles of the present processhave a uniform size, shape, and density, the chemical and metallurgicalnature of the catalyst may change, depending on processing objectivesand process conditions selected. For example, a catalyst selected for ademetallation application with minimum hydrocracking desired could bequite different in nature from a catalyst selected if maximumhydrodesulfurization and hydrocracking are the processing objectives.The type of catalyst selected in accordance with and having theproperties mentioned above, is disposed in any hydroconversion reactionzone. A hydrocarbon feed stream is passed through the catalyst,preferably passed through such as to upflow through the catalyst, inorder to hydroprocess the hydrocarbon feed stream. More preferably, thecatalyst is employed with the various embodiments of the presentinvention.

[0073] The process of the present invention is further illustrated withthe following specific example of the invention. In the example process,a hydrocarbon feed stream having a boiling point of greater than about343° C. and containing greater than 1 ppm metals and greater than 500ppm sulfur is introduced into a hydroconversion reaction zone whichcontains particulate hydroprocessing catalyst maintained at a reactionpressure, to commence upflowing of said hydrocarbon feed stream throughsaid catalyst and to recover a reaction effluent therefrom. Theproperties of the feed stream, the properties of the catalyst andreaction conditions, including flow rate, reaction temperature andreaction pressure, are selected to maintain the reactor system as asubstantially packed-bed type reactor system, where the catalyst andfluid velocity combinations limit bed expansion to less than 10% bylength beyond a substantially full axial length of the bed in a packedbed state. It is more preferred that the bed expansion be maintained atless than 5% and more preferred at less than 1% of the substantiallyfull axial length of the bed in a packed bed state. A preferred reactionpressure in the hydroconversion reaction zone is greater than 343° C.,and more preferably in the range of 343° C. to 482° C. A preferredreaction pressure in the hydroconversion reaction zone is greater than7.0 MPa (1000 psig), and more preferably in the range of 7.0 MPa to 24.2MPa (1000-3500 psig).

[0074] During the hydroprocess, a volume of hydroprocessing catalystwithin a treatment zone is sulfided to produce sulfided catalyst, and atleast a portion of the sulfided catalyst is added into thehydroconversion reaction zone while maintaining the reaction zone at thereaction pressure.

[0075] The hydroprocessing catalyst to be sulfided is either freshhydroprocessing catalyst or combinations of fresh hydroprocessingcatalyst and regenerated hydroprocessing catalyst. While additionalcomponents other than catalyst to be sulfided may be included in thevolume of hydroprocessing catalyst, it is generally not preferred. Avolume of the hydroprocessing catalyst is added to a treatment zone,such as by adding a slurry comprising a hydrocarbon liquid and thevolume of hydroprocessing catalyst to the treatment zone and removing atleast a portion of the hydrocarbon liquid from the treatment zone., andthe volume is heated until the catalyst has a temperature ranging from90° C. to 370° C. When the desired temperature is achieved, a sulfidingagent is added to the treatment zone to prepare sulfided catalyst. Asuitable sulfiding agent includes H₂S and H₂, typically in a molar ratioin the range 10:1 to 1:10.

[0076] An example method of adding sulfiding agent to the treatment zonecomprises introducing a H₂S containing gaseous material to the treatmentzone, pressurizing the treatment zone which contains the hydroprocessingcatalyst with a H₂ containing gas at a pressure in the range of 200 KPato 20,000 KPa and a temperature in the range of 90° C. to 370° C.,preferably in the range of 125-325° C., more preferably in the range of150-285° C. The catalyst in the treatment zone is maintained at thegiven pressure in contact with the sulfiding agent for a sufficienttime, generally less than 24 hours, preferably less than 10 hours, morepreferably less than 5 hours, to at least partially sulfide thecatalyst. The pressure in the treatment zone is then reduced and atleast a portion of the sulfiding agent is removed from the treatmentzone.

[0077] An alternative example method of adding sulfiding agent to thetreatment zone comprises adding a volume of hydroprocessing catalyst tothe treatment zone, which volume includes fresh hydroprocessingcatalyst; flowing a heated hydrocarbon liquid through the volume ofhydroprocessing catalyst within the treatment zone until the catalysthas a temperature ranging from 90° C. to 150° C.; subsequentlypressurizing the treatment zone at a pressure ranging from 0.2 MPa to24.2 MPa (15-3500 psig); continuing to flow the heated hydrocarbonliquid through the catalyst in the treatment zone until the catalyst hasa temperature ranging from 125° C. to 325° C.; flowing a sulfidingmixture through the catalyst in the treatment zone to prepare sulfidedcatalyst.

[0078] The sulfided hydroconversion catalyst is added to thehydroconversion reaction zone at a temperature greater than 125° C.,preferably greater than 150° C. and at a pressure of no less than thereaction pressure of the hydroconversion reaction zone. The method ofadding the sulfided hydroconversion catalyst to the hydroconversionreaction zone comprises adding a hydrocarbon liquid to the sulfidedcatalyst in the treatment zone; forming a slurry comprising thehydrocarbon liquid and at least a portion of the sulfided catalyst; andadding the slurry of the hydrocarbon liquid and the sulfided catalyst tothe hydroconversion reaction zone while maintaining the reaction zone atthe reaction pressure.

[0079] The reaction zone 10 contained within reactor vessel 11 ispreferably an upflow reaction system, with reacting fluids enteringreaction zone 10 through feed inlet 14, passing upward in upflow modethrough reaction zone 10 moving bed reactor, the reaction effluentexiting through conduit 16. The catalyst presulfiding process iseffective for reaction zones operated as a ebullating bed reactionsystem or as a substantially packed-bed type reactor system having anonstream catalyst replacement system (i.e. having a capability fortransferring catalyst to and from the reaction zone at substantiallyreaction pressure). To maintain the reactor system as a substantiallypacked-bed type reactor system, the onstream catalyst replacement systemis a counterflow processing system where the catalyst and fluid velocitycombinations limit bed expansion to less than 10% by length beyond asubstantially full axial length of the bed in a packed bed state. It ismore preferred that the bed expansion be maintained at less than 5% andstill more preferred at less than 1% of the substantially full axiallength of the bed in a packed bed state. A preferred substantiallypacked bed type reactor system is taught in U.S. Pat. No. 5,076,908 thedisclosure of which is incorporated herein by reference for allpurposes.

[0080] In carrying out the process of a preferred embodiment of thepresent invention as broadly illustrated in FIGS. 1, 2, a minimumaverage level of catalytic feed upgrading activity for thecountercurrently moving catalyst bed (e.g. catalyst bed 10) as a wholeis selected for the particular catalytic upgrading reaction. For amoving bed (e.g. catalyst bed 10) in a demetallation reaction system,for example, the minimum average upgrading activity level for thecatalyst bed is one which removes the necessary amount of metals fromthe hydrocarbon feed stream when it passes through the moving bed atdemetallation conditions. Similarly, for a desulfurization reactionsystem, the moving catalyst bed (e.g. catalyst bed 10) removes thenecessary amount of sulfur from the hydrocarbon feed stream when itpasses through the moving bed at desulfurization conditions. Thus, aswill be apparent to those skilled artisans, the minimum averageupgrading activity level for a particular reaction system will depend onthe desired degree of a contaminant, such as metals, sulfur, nitrogen,asphaltenes, etc., which the refiner desires to remove from the heavyoil feed. The degree of demetallation or desulfurization (or etc.) willtypically be set by economics and the downstream processing that theheavy feed will undergo.

[0081] A preferred upgrading use of the present invention is for feeddemetallation. For such upgrading, the temperatures and pressures withinthe reaction zone can be those typical for conventional demetallationprocessing. The pressure is typically above 3.45 MPa (500 psig). Thetemperature is typically greater than 315° C., and preferably above 371°C. Generally, the higher the temperature, the faster the metals areremoved; but the higher the temperature, the less efficiently the metalscapacity of the demetallation catalyst is used. While demetallationreaction can be conducted in the absence of added hydrogen, hydrogen isgenerally used and therefore requires full and equal distribution intothe moving bed along with any gases evolving from the feed. Morepreferred hydroprocessing conditions within the hydroconversion reactionzone to hydroprocess the hydrocarbon feed stream include a reactiontemperature in a temperature range 343°-482° C. (650°-900° F.) and areaction pressure in a pressure range of 7.0 MPa to 24.2 MPa (1000-3500psig).

[0082] The invention is illustrated by the following example of apreferred embodiment. A hydrocarbon feed stream in the presence ofhydrogen is introduced into a hydroconversion reaction zone whichcontains particulate hydroprocessing catalyst maintained at a reactionpressure, to commence upflowing of said hydrocarbon feed stream throughsaid catalyst and to recover a reaction effluent therefrom. The reactionpressure is preselected for the particularly process and reactionsdesired, and is typically greater than 3.6 MPa (500 psig), preferably inthe temperature range of 7.0 MPa to 24.2 MPa (1000-3500 psig). Thereaction temperature, which is sufficient to hydroprocess thehydrocarbon feed stream, is in a temperature range of 343°-482° C.(650°-900° F.). In the process, a first volume of the hydroprocessingcatalyst from the hydroconversion reaction zone is withdrawn whilemaintaining the reaction zone at the reaction pressure. Desirably, thehydroconversion reaction zone contains a substantially packed bed ofcatalyst, which commences to essentially plug-flow downwardly within thehydroconversion reaction zone when the first volume of hydroprocessingcatalyst is withdrawn therefrom.

[0083] The preferred process further comprises sulfiding a second volumeof hydroprocessing catalyst within a treatment zone to produce sulfidedcatalyst. In one preferred embodiment of the process, sulfided catalystis produced by adding a second volume of hydroprocessing catalyst to thetreatment zone, which second volume includes fresh hydroprocessingcatalyst; heating the second volume of hydroprocessing catalyst untilthe catalyst has a temperature ranging from 90° C. to 370° C.,preferably from 125° C. to 325° C.; and adding a sulfiding agent to thetreatment zone to prepare sulfided catalyst. If catalyst is added to thetreatment zone as a slurry in, e.g. a hydrocarbon stream, it may bedesired to remove at least a portion of the hydrocarbon stream prior tosulfiding. Sulfiding agent may be added by flowing the agent, or aliquid stream containing the agent, through the catalyst. Alternatively,sulfiding agent may be added by pressurizing a vessel containing thehydroprocessing catalyst in the treatment zone with the sulfiding agent.A sulfiding procedure involving pressurizing the catalyst in thetreatment zone with a sulfiding agent for a time sufficient to sulfidethe catalyst may include a step of reducing the pressure in thetreatment zone, and repressurizing the catalyst in the treatment zonewith a second quantity of sulfiding agent, to further sulfide thecatalyst. This cycle may be repeated until the catalyst is adequatelysulfided for the use desired.

[0084] To heat and/or sulfide the catalyst using flowing liquid streams,one preferred embodiment of the invention includes flowing a heatedhydrocarbon liquid through the second volume of hydroprocessing catalystwithin the treatment zone until the catalyst has a temperature rangingfrom 90° C. to 145° C.; subsequently pressurizing the treatment zone;continuing to flow the heated hydrocarbon liquid through the catalyst inthe treatment zone until the catalyst has a temperature ranging from125° C. to 325° C.; subsequently adding a sulfiding agent into theheated hydrocarbon liquid to produce a sulfiding mixture; flowing thesulfiding mixture through the catalyst in the treatment zone to preparesulfided catalyst. Preferred sulfiding agents include H₂S, such as theH₂S derived from a recycle stream recovered from the reaction effluent,dimethylsulfide and dimethyldisulfide. Catalyst may be sulfided in thepresent process at low temperature, e.g. at less than 370° C.,preferably in the temperature range 125-325° C., more preferably in thetemperature range 150°-285° C. Catalyst may be sulfided in a lowpressure vessel in the treatment zone at a pressure of 200 KPa (15 psig)or higher; in a high pressure vessel in the treatment zone at a pressurein the range of, for example, 7.0 MPa to 24.2 MPa (1000 psig to 3500psig), or in both.

[0085] Sulfided catalyst is added to the hydroconversion reaction zoneat a pressure higher than the reaction pressure, in order for thecatalyst to flow into the reaction zone. Suitably, the catalyst is addedto the reaction zone as a slurry in a hydrocarbon stream by adding ahydrocarbon liquid to the sulfided catalyst in the treatment zone;forming a slurry comprising the hydrocarbon liquid and at least aportion of the sulfided catalyst; and adding the slurry of thehydrocarbon liquid and the sulfided catalyst to the hydroconversionreaction zone.

Examples

[0086] The catalytic particulates comprised an alumina porous carriermaterial or alumina inorganic support. Deposited on and/or in thealumina porous carrier material was an oxidic hydrotreating catalystcomponent consisting of NiO and/or MoO₃. The Mo was present on and/or inthe alumina porous carrier material in an amount of about 3% by wt.,based on the combined weight of the alumina porous carrier material andthe oxidic hydrotreating catalyst component(s). The Ni was present onand/or in the alumina porous carrier material in an amount of about 1%by wt., based on the combined weight of the alumina porous carriermaterial and the oxidic hydrotreating catalyst component(s). The surfacearea of the catalytic particulates was about 120 sq. meters per gram.

[0087] The plurality of catalytic particulates were generally sphericalwith a mean diameter having a value ranging from about 6 Tyler mesh toabout 8 Tyler mesh and an aspect ratio of about 1. The mean crushstrength of the catalytic particulates was about 5 lbs. force. Themetals loading capacity of the catalyst or plurality of catalyticparticulates was about 0.3 grams of metal per cubic centimeter ofcatalytic particulate bulk volume.

[0088] A sample of the catalyst was loaded into a sulfiding reactor,heated at 205° C., and flooded with medium cycle oil (MCO). After 30minutes the medium cycle oil was drained, and MCO continued to pump overthe catalyst with the drain open for an additional 30 minutes. The flowof MCO was stopped and the excess oil allowed to drain from thecatalyst. The catalyst in the sulfiding reactor was then pressurizedwith 13.2 MPa of 5.0 vol % H₂S in H₂ for 2.5 hours. The sulfidingreactor containing the catalyst was then depressurized to 790 KPa andcooled to 38° C. The catalyst was flushed with heptane to remove theremaining MCO, dried and recovered for analysis. The sulfur content asshown in Run A of Table I is a percent of the amount of sulfur presenton a catalyst which was sulfided using dimethyldisulfide in a standardliquid sulfiding procedure at 316° C.

[0089] Table I also lists the sulfur content on catalysts sulfided usingthe procedure of Run A as described (e.g. Run B), using the procedure ofRun A but without flooding the catalyst initially with MCO (e.g. Run C),using the procedure of Run A but sulfiding at 316° C. (e.g. Run D) or at149° C. (e.g. Run E), or at 204° C. for 1.25 hours followed by 316° C.for 1.25 hours (e.g. Run F). The results in Table I show that, at theconditions of the experiment, the catalyst was adequately sulfided at204° C. using a single contacting cycle. The extent of sulfiding washigher at 204° C. than at either 149° C. or at 316° C. Two sulfidingcycles gave slightly better results than one cycle. The best results, interms of extent of sulfiding of the catalyst, occurred with thesulfiding temperature maintained at 204° C. for 1.25 hours followed by31 6° C. for 1.25 hours (Run F). TABLE I Run B C A E F Catalyst WettedWetted Dry Wetted Wetted Wetted Pretreatment with with with with withmedium medium medium medium medium cycle cycle cycle cycle cycle oil oiloil oil oil Sulfiding 204° C. 204° C. 204° C. 316° C. 149° C. 204° C./temperature 316° C.  Number of 1 2 1 1 1 1 sulfiding cycles Sulfiding2.5 2.5 2.5 2.5 2.5 2.5 time, each hours hours hours hours hours hourscycle Sulfur 76% 82% 77% 62.5% 69.1% 90.5% content of the sulfidedcatalyst

[0090] Three catalyst samples were tested: an H₂S presulfided catalystsample prepared as in Run A above (Sample G); a catalyst samplepresulfided using a standard dimethyldisulfide liquid presulfidingtreatment at 316° C. (Sample H); and a catalyst sample which was notpresulfided (Sample I).

[0091] Each catalyst sample was dropped into an Arab Heavy AtmosphericResiduum (4.3% Sulfur, 24.6 ppm nickel, 82.4 ppm vanadium and 11.3 APIgravity) heated to 371 ° C. to simulate dropping catalyst into a movingbed reactor at reaction temperature. The catalyst was removed from theresiduum after 24 hours, flushed with solvent, dried, and analyzed forthe sulfur content remaining. Catalyst Sample Sulfur content oncatalyst, wt % G 2.83 H 2.79 I 2.68

[0092] These results suggest that the total sulfur content wasessentially the same on each of the three catalyst samples.

[0093] Following the hot oil treatment, catalyst samples G, H and I weretested for desulftrization activity, using an atmospheric residuumfeedstock having the following properties Gravity, ° API 8.9 Sulfur, wt% 4.51 MCR, wt % 16.6 V, ppm 358 Ni, ppm 70 Asphaltenes, wt % 13.6Viscosity @ 100° C., cSt 285

[0094] The atmospheric residuum feedstock was contacted with H₂ overeach catalyst at 13.9 MPa pressure, a flow rate of 0.75 hr ⁻¹, and witha once-through hydrogen flow of 760 liters H₂/kg oil. For the first 250hours, the reaction temperature was maintained at 378° C. Between 250hours and 750 hours the reaction temperature was maintained at 402° C.

[0095]FIG. 3 is a normalized temperature plot showing the normalizedreaction temperature required to maintain a product sulfur content of2.2 wt % in the stripper bottoms product at 0.75 LHSV, assuming 1.5thorder kinetics and an activation energy of 30 kcal/gmole. As shown inFIG. 3, the catalyst presulfided using the H₂S treatment was 3.9° C.(7°F.) more active (i.e. lower reaction temperature) than the conventionalunsulfided catalyst. The catalyst presulfided using the more costlydimethyldisulfide presulfiding was 9.4° C.(17° F.) more active than theconventional unsulfided catalyst. These data show the surprising benefitof presulfiding the catalyst prior to adding the catalyst to a movingbed reaction system, even though the catalyst is presumed to be quicklysulfided once it is added to the reaction zone by the sulfur containingcomponents of the feed which is being processed.

What is claimed is:
 1. A method for the extension of cycle length of acatalyst employed in the hydroprocessing of a heavy hydrocarbon liquidstream, the hydroprocessing occurring in a moving bed reactor systemhaving at least one reaction zone and a pretreatment zone forpresulfiding the catalyst, wherein the heavy hydrocarbon stream isupflowing through the reaction zone, which contains the at leastpartially presulfided catalyst which has been at least partiallypresulfided within the treatment zone.
 2. The method of claim 2, themoving bed reactor system being selected from a group consisting of:(ii) a fixed bed reactor system; (ii) ebullated and expanded types ofreactor systems which are capable of onstream catalyst replacement;(iii) a substantially packed-bed type reactor system having an onstreamcatalyst replacement system.
 3. The method of claim 1, in which theheavy hydrocarbon liquid stream is an atmospheric residuum.
 4. Themethod according to claim 1, wherein the catalyst is presulfided in thetreatment zone by means of the following steps: a) adding a volume ofhydroprocessing catalyst to the treatment zone, which volume includesfresh hydroprocessing catalyst; b) heating the volume of hydroprocessingcatalyst until the catalyst has a temperature ranging from 90° C. to370° C.; and c) adding a presulfiding agent to the treatment zone toprepare presulfided catalyst.
 5. The method according to claim 4,wherein hydroprocessing catalyst is sulfided at a temperature of 125° C.to 325° C.
 6. The method according to claim 4, wherein the step ofadding a volume of hydroprocessing catalyst to the treatment zonecomprises: a) preparing a slurry comprising a hydrocarbon liquid and avolume of hydroprocessing catalyst; b) adding the slurry comprising thehydrocarbon liquid and the hydroprocessing catalyst to the treatmentzone; and c) removing at least a portion of the hydrocarbon liquid fromthe treatment zone.
 7. The method according to claim 4, wherein the stepof adding a presulfiding agent to the treatment zone comprises: a)pressurizing the treatment zone which contains the hydroprocessingcatalyst with a presulfiding agent at a pressure in the range of 0.2 to24.2 MPa and a temperature in the range of 90° C. to 370° C. to produceat least partially presulfided catalyst; and b) removing at least aportion of the presulfiding agent from the treatment zone.
 8. The methodaccording to claim 7, wherein the presulfiding agent comprises a sulfurcontaining material selected from the group consisting of H₂S andsulfur-containing materials which decompose at temperatures below about370° C.
 9. The method according to claim 8, wherein the presulfidingagent comprises H₂S.
 10. The method according to claim 9, wherein thepresulfiding agent comprises a gaseous recycle stream containing H₂ andH₂S.
 11. The method of claim 7, wherein the at least partiallypresulfided catalyst is produced at a temperature in the range of 125°C. to 325° C. and at a pressure in the range of 5.0 MPa to 20 MPa. 12.The method of claim 11, wherein the at least partially presulfidedcatalyst is produced at a temperature in the range of 150° C. to 285° C.13. The method according to claim 4, wherein the step of adding apresulfiding agent to the treatment zone comprises: a) adding a volumeof hydroprocessing catalyst to the treatment zone, which volume includesfresh hydroprocessing catalyst; b) flowing a heated hydrocarbon liquidthrough the volume of hydroprocessing catalyst within the treatment zoneuntil the catalyst has a temperature ranging from 90° C. to 145° C.; c)subsequently pressurizing the treatment zone at a pressure ranging from0.2 MPa to 24.2 MPa (15-3500 psig); d) continuing to flow the heatedhydrocarbon liquid through the catalyst in the treatment zone until thecatalyst has a temperature ranging from 125° C. to 325° C.; e) flowing apresulfiding mixture through the catalyst in the treatment zone toprepare at least partially presulfided catalyst.
 14. The method of claim13, wherein the at least partially presulfided catalyst is produced at atemperature in the range of 150° C. to 285° C.
 15. A method forhydroprocessing a hydrocarbon feed stream that is upflowing through ahydroconversion reaction zone comprising the steps of: a) introducing ahydrocarbon feed stream in the presence of hydrogen at a reactionpressure into a hydroconversion reaction zone which contains particulatehydroprocessing catalyst to commence upflowing of said hydrocarbon feedstream through said catalyst and to recover a reaction effluenttherefrom; b) presulfiding a volume of hydroprocessing catalyst within atreatment zone to produce presulfided catalyst, wherein the catalyst ispresulfided by means of the following steps: (1) adding a volume ofhydroprocessing catalyst to the treatment zone, which volume includesfresh hydroprocessing catalyst; (2) heating the volume ofhydroprocessing catalyst until the catalyst has a temperature rangingfrom 90° C. to 370° C.; and (3) adding a sulfiding agent to thetreatment zone to prepare presulfided catalyst; and c) adding at least aportion of the sulfided catalyst into the hydroconversion reaction zonewhile maintaining the reaction zone at the reaction pressure.
 16. Themethod according to claim 15, wherein the step of adding at least aportion of the presulfided catalyst into the hydroconversion reactionzone comprises: a) adding a hydrocarbon liquid to the presulfidedcatalyst in the treatment zone; b) forming a slurry comprising thehydrocarbon liquid and at least a portion of the presulfided catalyst;and c) adding the slurry of the hydrocarbon liquid and the presulfidedcatalyst to the hydroconversion reaction zone while maintaining thereaction zone at the reaction pressure.
 17. The method according toclaim 16, wherein the slurry is added to the hydroconversion reactionzone at a temperature in the range from 125° C. to 325° C.
 18. A methodfor hydroprocessing a hydrocarbon feed stream that is upflowing througha hydroconversion reaction zone comprising the steps of: a) introducinga hydrocarbon feed stream in the presence of hydrogen at a reactionpressure into a hydroconversion reaction zone which contains particulatehydroprocessing catalyst to commence upflowing of said hydrocarbon feedstream through said catalyst and to recover a reaction effluenttherefrom; b) presulfiding a volume of hydroprocessing catalyst at apressure in the range of 0.2 to 7.0 MPa and a temperature in the rangeof 90° C. to 370° C. within a treatment zone to produce at leastpartially sulfided catalyst; and c) adding at least a portion of thepresulfided catalyst into the hydroconversion reaction zone whilemaintaining the reaction zone at the reaction pressure.
 19. The methodaccording to claim 18, wherein the hydroprocessing catalyst ispresulfided at a pressure in the range of 0.2 to 3.5 MPa and at atemperature in the range of 125° C. to 325° C.
 20. The method of claim18 further comprising presulfiding the partially presulfided catalyst ata pressure in the range of 7.0 MPa to 24.2 MPa and a temperature in therange of 90° C. to 370° C.
 21. The method according to claim 20, whereinthe partially presulfided catalyst is presulfided at a temperature inthe range of 125° C. to 325° C.
 22. The process according to claim 15,wherein the hydroconversion reaction zone is maintained at a reactionpressure and at a reaction temperature sufficient to hydroprocess thehydrocarbon feed stream, including a reaction temperature in atemperature range 343° C.-482° C. and a reaction pressure in a pressurerange from 7.0 MPa to 24.2 MPa (1000-3500 psig).
 23. The processaccording to claim 15, wherein the reaction zone is maintained as asubstantially packed bed of particulates hydroprocessing catalyst. 24.The method of claim 23, wherein the step of introducing a hydrocarbonfeed stream into a hydroconversion reaction zone comprises flowingupwardly said hydrocarbon feed stream into said substantially packed bedof hydroprocessing catalyst at a rate of flow such that saidsubstantially packed bed of hydroprocessing catalyst expands to lessthan 10% by length beyond a substantially full axial length of saidsubstantially packed bed of hydroprocessing catalyst in a packed bedstate.
 25. A method for hydroprocessing a hydrocarbon feed streamcomprising the steps of: a) introducing a hydrocarbon feed stream into ahydroconversion reaction zone having a substantially packed bed ofparticulate hydroprocessing catalyst to commence upflowing of saidhydrocarbon feed stream through said substantially packed bed of thecatalyst at a rate of flow such that said substantially packed bed ofhydroprocessing catalyst expands to less than 10% by length beyond asubstantially full axial length of said substantially packed bed ofhydroprocessing catalyst in a packed bed state, and to recover areaction effluent therefrom; b) withdrawing a first volume of thehydroprocessing catalyst from the hydroconversion reaction zone tocommence essentially plug-flowing downwardly said substantially packedbed of hydroprocessing catalyst within said hydroconversion reactionzone; c) adding a second volume of a particulate hydroprocessingcatalyst to a treatment zone, which second volume includes freshhydroprocessing catalyst; d) presulfiding the second volume ofhydroprocessing catalyst within the treatment zone to preparepresulfided catalyst; and e) adding at least a portion of thepresulfided catalyst into the hydroconversion reaction zone to replacethe withdrawn first volume of catalyst.
 26. The method according toclaim 25, wherein the step of presulfiding a second volume ofhydroprocessing catalyst within the treatment zone comprises: a) addinga volume of hydroprocessing catalyst to the treatment zone, which volumeincludes fresh hydroprocessing catalyst; b) heating the volume ofhydroprocessing catalyst until the catalyst has a temperature rangingfrom 90° C. to 370° C.; and c) adding a presulfiding agent to thetreatment zone to prepare sulfided catalyst.
 27. The method according toclaim 26, wherein hydroprocessing catalyst is presulfided at atemperature of 125° C. to 325° C.
 28. The method according to claim 26,wherein the step of adding a volume of hydroprocessing catalyst to thetreatment zone comprises: a) preparing a slurry comprising a hydrocarbonliquid and a volume of hydroprocessing catalyst; b) adding the slurrycomprising the hydrocarbon liquid and the hydroprocessing catalyst tothe treatment zone; and c) removing at least a portion of thehydrocarbon liquid from the treatment zone.
 29. The method according toclaim 26, wherein the step of adding a presulfiding agent to thetreatment zone comprises: a) pressurizing the treatment zone whichcontains the hydroprocessing catalyst with a presulfiding agent at apressure in the range of 0.2 to 24.2 MPa and a temperature in the rangeof 90° C. to 370° C. to produce at least partially presulfided catalyst;and b) removing at least a portion of the presulfiding agent from thetreatment zone.
 28. The method according to claim 29, wherein thepresulfiding agent comprises a sulfur containing material selected fromthe group consisting of H₂S and sulfur-containing materials whichdecompose at temperatures below 370° C.
 29. The method according toclaim 28, wherein the presulfiding agent comprises H₂S.
 30. The methodaccording to claim 29, wherein the presulfiding agent comprises agaseous recycle stream containing H₂ and H₂S.
 31. The method of claim29, wherein the at least partially presulfided catalyst is produced at atemperature in the range of 125° C. to 325° C.
 32. The method of claim31, wherein the at least partially presulfided catalyst is produced at atemperature in the range of 150° C. to 285° C.
 33. The method accordingto claim 26, wherein the step of adding a presulfiding agent to thetreatment zone comprises: a) adding a volume of hydroprocessing catalystto the treatment zone, which volume includes fresh hydroprocessingcatalyst; b) flowing a heated hydrocarbon liquid through the volume ofhydroprocessing catalyst within the treatment zone until the catalysthas a temperature ranging from 90° C. to 145° C.; c) subsequentlypressurizing the treatment zone at a pressure ranging from 0.2 MPa to24.2 MPa (15-3500 psig); d) continuing to flow the heated hydrocarbonliquid through the catalyst in the treatment zone until the catalyst hasa temperature ranging from 125° C. to 325° C.; e) flowing a presulfidingmixture through the catalyst in the treatment zone to prepare at leastpartially sulfided catalyst.
 34. The method of claim 33, wherein the atleast partially presulfided catalyst is produced at a temperature in therange of 150° C. to 285° C.
 35. The method according to claim 25,wherein the at least partially presulfided catalyst into thehydroconversion reaction zone comprises: a) adding a hydrocarbon liquidto the sulfided catalyst in the treatment zone; b) forming a slurrycomprising the hydrocarbon liquid and at least a portion of thepresulfided catalyst; and c) adding the slurry of the hydrocarbon liquidand the presulfided catalyst to the hydroconversion reaction zone whilemaintaining the reaction zone at the reaction pressure.
 36. The methodaccording to claim 35, wherein the slurry is added to thehydroconversion reaction zone at a temperature in the range from 125° C.to 325° C.